Describe "Removing a TE" operation

Signed-off-by: Manish Pandey <manish.pandey2@arm.com>

Author: manish-pandey-arm

source/transfer_list.rst

@@ -292,6 +292,8 @@ This section describes the valid operations that may be performed on a TL in
 more detail, in order to clarify how to use the various fields and to serve as a
 guideline for implementation.
 
+.. _validate TL header:
+
 Validating a TL header
 ^^^^^^^^^^^^^^^^^^^^^^
 
@@ -409,6 +411,27 @@ Inputs:
    #. If `has_checksum`, xor the 8 bytes from `te_base_addr` to
       `te_base_addr + 0x8` with `tl.checksum`.
 
+Removing a TE
+^^^^^^^^^^^^^
+
+Inputs:
+
+- `tl_base_addr`: Base address of the TL from which TE to be deleted.
+- `tag_id`: ID number of the tag to be deleted.
+
+#. Validate the TL header as mentioned in :ref:`validate TL header`
+
+#. Locate the `te_base_addr` of the TE to be removed by iterating through the TL.
+
+#. Mark the TE as void by setting its tag_id to XFERLIST_VOID
+
+#. Update `te.data_size` to ensure it remains 8-byte aligned
+
+#. *(optional)*  Erase the TE data if there is a risk of exposing sensitive information
+   to the next consumer
+
+#. If checksum is enabled, recalculate and update tl.checksum
+
 Adding a new TE with special data alignment requirement
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^